Ports and rivertowns in the Siphonian deeps look, sound and smell different than Earth ports, and much of the muskiness and noise is due to this species. Big wet furry things chirp at you and wiggle their whiskers. They're descendants of giant freshwater Amazonian otters, of course.

Creatures adapted to the Siphonian Deeps in diverse ways. Otters' quick evolution was one of those unpredictable consequences of radical environmental change. Recent studies show that the size of animals and the number of species (and probably total biomass, too) correlate well with the oxygen content of the air. Earth's atmosphere has varied greatly over its history--in the last billion years alone, it's varied from 13 to 30% oxygen! While the percentage of oxygen on Siphonia isn't much higher than on our Earth, the dense rainforests in the deepest basins have raised it to 21 or 22%. However, that's merely the percentage. In the Pacific Deeps--the quintessential Siphonian abyss--air pressure's so high that 70-80% more oxygen is available. A bigger change than animal life has seen since brains evolved! All that extra oxygen makes it much easier for an animal to grow larger--OR to grow larger specialized, oxygen-hungry organs. Like brains! They're the costliest organ of all, pound for pound, measured in both calorie- and oxygen-consumption. In an environment where food isn't too hard to get (and these exuberant jungle coasts certainly qualify) it turns out that supercharged air has freed many nonflying species to grow much larger and more intelligent.

Amazonian otters, already big and smart, apparently crossed a crucial threshhold: social intelligence, the ability to understand, predict, and influence other creatures' behavior, became more important as they got less predictable. A spiral of brain-growth ensued, rather quickly tripling brain-size, precisely as it already had in humans, bottlenose dolphins, and probably elephants in our world, and to ravens, parrots, cockatoos, and half a dozen other species in the Siphonian abyss.

Other than skull size, the otters haven't changed that much, physically. They're omnivorous now, of course; the jungles of the Deep are too rich in fruit, nuts, buds, flowers, roots and tasy bugs not to take advantage of. Better thumbs, of course--though they were always pretty good at snatching fish, they now grasp a pen as dexterously as any human, and climb trees better.

The most visible adaptation is to the fierce, muggy heat of the Deeps. Most modern otters are gracile--slender with rangy limbs. More surface area per pound means a cooler otter: more evaporative heat dispersal when they're on land. Of course, in tropical abysses, otters may hardly come out of the water during the day-heat, but even the water's close to blood-warm, so even a swimming otter needs to be slender to stay cool.

But skinny otters aren't universal. There are no otter races, exactly--too many sailors spread their genes all over the Deeps--but there's a definite gradient. At high latitudes and altitudes, otters tend to regress to sleek and chubby, much like their ancestors. The sketch (above left) shows an Orcadian otter, a good example of this type, on vacation in a subalpine meadow of the Sandwich Range bordering Scotia Deep--the rugged basin between our Tierra Del Fuego and Antarctica. The tourist season here is only a few months long, but still... this really ain't the tropics.

On the other paw, in the equatorial Deeps many otters look almost anorexic, at least to the northerners. To the right is a sketch of a Cearan (a native of the sweltering equatorial isle of Ceara off the Amazon Delta in the Atlantic Deep), speaking up at a village meeting. She's not anorexic at all, of course; gracile otters are just as voracious (and vivacious) as their curvier cousins. But that doesn't stop Scotians and Orcadians from teasing Cearans for being bony. As the Orcadian sea-chanty goes,

Not that you'd hear that chorus on any tropical voyage. And I won't quote the song popular in the dockside bars of Bengal about fat, stupid otters of the Ganges Plateau; it's just mean.

HABITAT

While very few otters live outside the Deeps, a few do. They still live in their ancestral home the Amazon Upland and have spread to other mild equatorial plateaus like Arafura and the Congo.

They're no longer strictly tropical, either. Within the Deeps, their range extends to fairly high latitudes. Some otters now live below glacial peaks at the mouth of the Cook River in the the Antipode Sea, and on the slopes of the Aleut Range in the northern Pacific. Such coasts are much warmer than our subpolar regions, of course--the dense air guarantees it never quite snows on the coast, not at latitude 50, and not much even at 60--but still, they've come a long, long way from the muddy tributaries of the equatorial Amazon.

Of course, mentally they've come further still; from (admittedly bright) animals to people in a geological blink. Maybe there's something to this optimism thing.

BEHAVIOR

Otter behavior? Well... all the cliches are true. Otters really are as playful and good-natured as you think. But their dexterity and cunning rival their social skill--as many otters are civic engineers as sushi chefs, sculptors, or clowns. Far more, of course, have more mundane work: fishers, sailors, traders, and dockworkers.

Otter culture is earthy, humorous, social and sensual. Otters wrestle and play unhinhibitedly. Affection grades into sex pretty casually. Bar scenes tend to be rowdy, though part of that may just be sailor-culture. Notably, though, fights are rare. In settling disputes and impressing potential mates, song-duels are more common than fighting.

Music matters. All otters sing at the slightest provocation, though they're loud and squeaky--otters' hearing range goes well above that humans.